PCSTATS has a
pile of benchmarks and Super Talent W1866UX2G8 DDR3-1866 overclocking tests
ready for you, so if you're already familiar with what separates DDR3 from DDR2 skip
ahead to the next page of this article.
Okay, DDR3...
As your geek friend has probably told you, desktop computer memory is in a transitory
phase. No one expects DDR3 to really take hold until 2008, when quad-core
processors take hold of the PC landscape completely. It's hard to say where
AMD will fall in with all of this, its 'K10' microprocessor architecture is not expected
to adopt DDR3 RAM until 2009. By then prices will be a lot
lower, and speeds much higher. :-)
Differences in memory: DDR2 and DDR3 are not
interpretable
As with all new standards, it's important to state the obvious
right from the start to minimize confusion. While DDR2 and DDR3 RAM Dual
Inline Memory Modules (DIMMs) are physically the same size, and contain the same
number of little gold connector pins (240), the RAM sticks are keyed differently and
are not interchangeable.
DDR3 RAM like the Super Talent W1866UX2G8 DDR3-1866 modules will not work
in a DDR2 motherboard even if the chipset is technically DDR3 compatible
(ie. Intel P35 Express). Conversely, DDR3 memory slots are not backwards compatible
with DDR2 memory modules.
|
These
are 1.5V DDR3 memory slots (above), looks pretty much exactly like DDR2
doesn't it? Below you can see a DDR3 memory module over top of a DDR2
module. Note the subtle difference where the DDR3 module is 'keyed' with
respect to the DDR2 module. Both memory standards have exactly 240 gold
connectors, but DDR3 operates at 1.5V, DDR2 at 1.8V.
 |
New memory
standards are almost always made incompatible with old ones, usually voltage and
data transfer architectures are to blame.
|
Placed edge
to edge, it is easy to see the physical difference between DDR2 and DDR3
modules rests with where that small key space is positioned. It prevents
DDR2 memory from being installed in a DDR3 motherboard and vice versa. The
pins line up perfectly.
|
One obvious
difference between DDR-3 memory and its predecessor is that DDR3 operates with
less voltage. DDR-3 RAM runs with 1.5V, while DDR2 demands a little more, 1.8V.
Next, unique memory slots prevent you from running DDR3 memory in a DDR2 memory
slot and vice versa. The memory standards themselves are not interoperable, so
neither are the sockets.
JEDEC
standards dictate
desktop DDR2 memory speeds to between 400-800 MHz, although chipset and memory
manufacturers have pushed DDR2 speeds much further. The JEDEC standard for DDR3 memory starts at 800 MHz,
running as high as 1600 MHz. While there is a bit of overlap in terms of speeds, it's
not likely to last.
At the moment most DDR3
memory is coming in two flavors, 1066 and 1333 MHz.
The speed will increase as the memory standard matures.
PCSTATS Test Methodology:
On Intel
Socket 775 Core 2 Duo test systems, we're only interested in seeing how high we
can go with the DDR3 memory running 1:2, as running with other dividers puts the
overclocking bottleneck elsewhere and not with the system memory. The DDR3 RAM
latency must run at its lowest possible setting, as quick access is more
important to the CPU design. Just for arguments sake, we will also be conducting
overclocking tests to see how high the memory will go with lax timings
(8-8-8-24), although we will only benchmark the system with the tight memory
timings mentioned above.
Let's get
started, overclocking is
next!!
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